Systems and methods for commanded reconfiguration of a surgical manipulator using the null-space

ABSTRACT

Devices, systems, and methods for reconfiguring a surgical manipulator by moving the manipulator within a null-space of a kinematic Jacobian of the manipulator arm. In one aspect, in response to receiving a reconfiguration command, the system drives a first set of joints and calculates velocities of the plurality of joints to be within a null-space. The joints are driven according to the reconfiguration command and the calculated movement so as to maintain a desired state of the end effector or a remote center about which an instrument shaft pivots. In another aspect, the joints are also driven according to a calculated end effector or remote center displacing velocities within a null-perpendicular-space of the Jacobian so as to effect the desired reconfiguration concurrently with a desired movement of the end effector or remote center.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a Non-Provisional of and claims the benefit ofpriority from U.S. Provisional Patent Application No. 61/654,764 filedon Jun. 1, 2012 and entitled “Commanded Reconfiguration of a SurgicalManipulator Using the Null-Space” (Attorney Docket No.ISRG03770PROV/US), the full disclosure of which is incorporated hereinby reference.

The present application is generally related to the followingcommonly-owned applications: U.S. application Ser. No. 12/494,695 filedJun. 30, 2009, entitled “Control of Medical Robotic System ManipulatorAbout Kinematic Singularities;” U.S. application Ser. No. 12/406,004filed Mar. 17, 2009, entitled “Master Controller Having RedundantDegrees of Freedom and Added Forces to Create Internal Motion;” U.S.application Ser. No. 11/133,423 filed May 19, 2005 (U.S. Pat. No.8,004,229), entitled “Software Center and Highly Configurable RoboticSystems for Surgery and Other Uses;” U.S. application Ser. No.10/957,077 filed Sep. 30, 2004 (U.S. Pat. No., 7,594,912), entitled“Offset Remote Center Manipulator For Robotic Surgery;” U.S. applicationSer. No. 09/398,507 filed Sep. 17, 1999 (U.S. Pat. No. 6,714,839),entitled “Master Having Redundant Degrees of Freedom;” and U.S.application Ser. Nos. ______ [Atty Docket No. ISRG03760/US] entitled“Manipulator Arm-to-Patient Collision Avoidance Using a Null-Space;” and______ [Atty Docket No. ISRG03810/US] entitled “Systems and Methods forAvoiding Collisions Between Manipulator Arms Using a Null-Space” filedconcurrently with the present application; the disclosures of which areincorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

The present invention generally provides improved surgical and/orrobotic devices, systems, and methods.

Minimally invasive medical techniques are aimed at reducing the amountof tissue which is damaged during diagnostic or surgical procedures,thereby reducing patient recovery time, discomfort, and deleterious sideeffects. Millions of “open” or traditional surgeries are performed eachyear in the United States; many of these surgeries can potentially beperformed in a minimally invasive manner. However, only a relativelysmall number of surgeries currently use minimally invasive techniquesdue to limitations in surgical instruments, and techniques, and theadditional surgical training required to master them.

Minimally invasive telesurgical systems for use in surgery are beingdeveloped to increase a surgeon's dexterity as well as to allow asurgeon to operate on a patient from a remote location. Telesurgery is ageneral term for surgical systems where the surgeon uses some form ofremote control, e.g., a servomechanism, or the like, to manipulatesurgical instrument movements rather than directly holding and movingthe instruments by hand. In such a telesurgery system, the surgeon isprovided with an image of the surgical site at the remote location.While viewing typically a three-dimensional image of the surgical siteon a suitable viewer or display, the surgeon performs the surgicalprocedures on the patient by manipulating master control input devices,which in turn control the motion of robotic instruments. The roboticsurgical instruments can be inserted through small, minimally invasivesurgical apertures to treat tissues at surgical sites within thepatient, often the trauma associated with accessing for open surgery.These robotic systems can move the working ends of the surgicalinstruments with sufficient dexterity to perform quite intricatesurgical tasks, often by pivoting shafts of the instruments at theminimally invasive aperture, sliding of the shaft axially through theaperture, rotating of the shaft within the aperture, and/or the like.

The servomechanism used for telesurgery will often accept input from twomaster controllers (one for each of the surgeon's hands) and may includetwo or more robotic arms or manipulators. Mapping of the hand movementsto the image of the robotic instruments displayed by the image capturedevice can help provide the surgeon with accurate control over theinstruments associated with each hand. In many surgical robotic systems,one or more additional robotic manipulator arms are included for movingan endoscope or other image capture device, additional surgicalinstruments, or the like.

A variety of structural arrangements can be used to support the surgicalinstrument at the surgical site during robotic surgery. The drivenlinkage or “slave” is often called a robotic surgical manipulator, andexample linkage arrangements for use as a robotic surgical manipulatorduring minimally invasive robotic surgery are described in U.S. Pat.Nos. 6,758,843; 6,246,200; and 5,800,423, the full disclosures of whichare incorporated herein by reference. These linkages often make use of aparallelogram arrangement to hold an instrument having a shaft. Such amanipulator structure can constrain movement of the instrument so thatthe instrument shaft pivots about a remote center of spherical rotationpositioned in space along the length of the rigid shaft. By aligningthis center of rotation with the incision point to the internal surgicalsite (for example, with a trocar or cannula at an abdominal wall duringlaparoscopic surgery), an end effector of the surgical instrument can bepositioned safely by moving the proximal end of the shaft using themanipulator linkage without imposing potentially dangerous forcesagainst the abdominal wall. Alternative manipulator structures aredescribed, for example, in U.S. Pat. Nos. 6,702,805; 6,676,669;5,855,583; 5,808,665; 5,445,166; and 5,184,601, the full disclosures ofwhich are incorporated herein by reference.

While the new robotic surgical systems and devices have proven highlyeffective and advantageous, still further improvements would bedesirable. For example, when moving the surgical instruments within aminimally invasive surgical site, robotic surgical manipulators mayexhibit a significant amount of movement outside the patient,particularly when pivoting instruments about minimally invasiveapertures through large angular ranges, which can lead to the movingmanipulators inadvertently coming into contact with each other, withinstrument carts or other structures in the surgical room, with surgicalpersonnel, and/or with the outer surface of the patient. Alternativemanipulator structures have been proposed which employ software controlover a highly configurable kinematic manipulator joint set to restrainpivotal motion to the insertion site while inhibiting inadvertentmanipulator/manipulator contact outside the patient (or the like). Thesehighly configurable “software center” surgical manipulator systems mayprovide significant advantages, but may also present challenges. Inparticular, the mechanically constrained remote-center linkages may havesafety advantages in some conditions. Additionally, the wide range ofconfigurations of the numerous joints often included in thesemanipulators may result in the manipulators being difficult to manuallyset-up in a configuration that is desirable for a particular procedure.Nonetheless, as the range of surgeries being performed usingtelesurgical systems continues to expand, there is an increasing demandfor expanding the available configurations and the range of motion ofthe instruments within the patient. Unfortunately, both of these changescan increase the challenges associated with the motion of themanipulators outside the body, and can also increase the importance ofavoiding manipulator configurations that are poorly conditioned (suchthat they unnecessarily limit the dexterity and/or range of motion ofthe tool inside the surgical workspace).

For these and other reasons, it would be advantageous to provideimproved devices, systems, and methods for surgery, robotic surgery, andother robotic applications. It would be particularly beneficial if theseimproved technologies provided the ability to reconfigure themanipulator arms according to a desired reconfiguration whilemaintaining a desired end effector state or a desired location of aremote center about which the instrument shaft pivots. Ideally, theseimprovements would allow a first user to effect movement of an endeffector of the manipulator arm during a surgical procedure whileallowing a second user to reconfigure the manipulator arms inpreparation for and/or during end effector movement. Additionally, itwould be desirable to provide such improvements while increasing therange of motion of the instruments for at least some procedures andwithout significantly increasing the size, mechanical complexity, orcosts of these systems, and while maintaining or improving theirdexterity.

BRIEF SUMMARY OF THE INVENTION

The present invention generally provides improved robotic and/orsurgical devices, systems, and methods. In many embodiments, theinvention will employ highly configurable surgical robotic manipulators.These manipulators, for example, may have more degrees of freedom ofmovement than the associated surgical end effectors have within asurgical workspace. A robotic surgical system in accordance with thepresent invention typically includes a manipulator arm supporting arobotic surgical instrument and a processor to calculate coordinatedjoint movements for manipulating an end effector of the instrument. Thejoints of the robotic manipulators supporting the end effectors allowthe manipulator to move throughout a range of different configurationsfor a given end effector position and/or a given pivot point location.The system allows for reconfiguration of the highly configurable roboticmanipulators, in response to a user command, by driving one or morejoints of the manipulator according to coordinated movement of thejoints calculated by a processor, resulting in the motion of one or morejoints of the manipulator within a null-space of the kinematic Jacobianso as to maintain the desired end effector state and/or pivot pointlocation. In various embodiments, a system operator enters areconfiguration command with a user input device and drives one or morejoints of the manipulator within the null-space until the manipulator isreconfigured as desired.

In one aspect of the present invention, a redundant degrees of freedom(RDOF) surgical robotic system with manipulate input is provided. TheRDOF surgical robotic system comprises a manipulator assembly, one ormore user input devices, and a processor with a controller. Amanipulator arm of the assembly has a plurality of joints providingsufficient degrees of freedom that allow a range of joint states for agiven end effector state. In response to a received reconfigurationcommand entered by a user, the system calculates velocities of theplurality of joints within a null-space. The joints are driven accordingto the reconfiguration command and the calculated movement so as tomaintain the desired state of the end effector. In response to receivinga manipulation command to move the end effector with a desired movement,the system calculates end effector displacing movement of the joints bycalculating joint velocities within a null-perpendicular-space of theJacobian orthogonal to the null-space and drives the joints according tothe calculated movement to effect the desired end effector movement.

In another aspect of the present invention, the manipulator isconfigured to move such that an intermediate portion of the instrumentshaft pivots about a remote center. Between the manipulator and theinstrument, there are a plurality of driven joints providing sufficientdegrees of freedom to allow a range of joint states for an end effectorposition when the intermediate portion of the instrument shaft extendsthrough an access site. A processor having a controller couples theinput device to the manipulator. In response to a reconfigurationcommand, the processor determines movements of one or more joints toeffect the desired reconfiguration so that the intermediate portion ofthe instrument is within the access site during the end effector'sdesired movement and maintains the desired remote center location aboutwhich the shaft pivots. In various embodiments, in response to receivinga manipulation command to effect a desired end effector's movement, thesystem calculates end effector displacing movement of the joints, whichcomprises calculating joint velocities within a null-perpendicular-spaceof the Jacobian orthogonal to the null-space and drives the jointsaccording to the calculated movement to effect the desired end effectormovement in which the instrument shaft pivots about the remote center.

In certain embodiments, the end effector displacing movement of thejoints is calculated so as to avoid driving a first set of joints of theplurality such that either the first set of joints are effectivelylocked out, or so that the first set of joints are not driven to effectthe end effector displacing movement. The first set of joints mayinclude one or more joints of the manipulator arm. The reconfigurationmovements of the joints, however, may be calculated so as to drive thefirst set of joints of the plurality to effect the desired end effectormovement. The reconfiguration movement of the first set of joints mayalso be calculated so that the movement of a joint from the first set ofjoints provides a substantially constant speed of the joint for aduration of the reconfiguration. In some embodiments, a joint from thefirst set of joints of the manipulator is a revolute joint coupling themanipulator arm to the base. The desired state of the end effector mayinclude a desired position, velocity or acceleration of the endeffector. Generally, the manipulation command and the reconfigurationcommand are separate inputs, typically being received from separateusers on separate input device, or these separate inputs may be receivedfrom the same user. In some embodiments, the end effector manipulationcommand is received from an input device by a first user, such as asurgeon entering the command on a surgical console master input, whilethe reconfiguration command is received from an input device by a seconduser on a separate input device, such as a physician's assistantentering the reconfiguration command on a patient side cart inputdevice. In other embodiments, the end effector manipulation command andthe reconfiguration command are both received by the same user frominput devices at a surgical console. In other embodiments, the endeffector manipulation command and the reconfiguration command are bothreceived by the same user from input devices at a patient side cart.

In one aspect, the proximal portion of the manipulator arm is attachedto the base such that movement of the proximal portion relative to thebase is inhibited while the joints are driven. The proximal portion maybe coupled to the base by a joint such that the proximal portion of themanipulator arm is moveable relative to the base while the joints aredriven. In an example embodiment, the joint coupling the proximalportion of the manipulator to the base by a revolute joint that supportsthe manipulator arm such that joint movement of the revolute jointpivots one or more joints of the manipulator arm about a pivotal axis ofthe revolute joints. In certain embodiments, the pivotal axis of therevolute joint extends from the joints through a remote center aboutwhich an instrument shaft of the end effector pivots. In one aspect,movement of the revolute joint pivots one or more joints of themanipulator arm about a cone distally tapered and oriented towards thedistal end effector, typically the remote center. The cone around whichthe manipulator arm pivots in this aspect, corresponds to a cone shapedvoid within the range of motion of the tool tip, in which the movementof the tool may be impossible or impaired, discussed in further detailbelow.

In another aspect, the joint coupling the proximal portion of themanipulator to the base is moveable relative to the base along a path,typically an arcuate or substantially circular path such that movementof the joint along the path pivots one or more joints of the manipulatorarm about an axis extending through a distal portion of the manipulatorarm near the instrument, preferably through a remote center about whichthe instrument shaft pivots. In some embodiments, the manipulatorincludes a revolute joint coupling the proximal portion of themanipulator to the base, the revolute joint being moveable relative tothe base along a path, which may linear, arcuate or substantiallycircular.

In yet another aspect of the present invention, a surgical roboticmanipulator with a proximal revolute joint and a distal parallelogramlinkage is provided, the pivotal axis of the revolute jointsubstantially intersecting with the axis of the instrument shaft of theend effector, preferably at a remote center if applicable. The systemfurther includes a processor having a controller coupling the input tothe manipulator arm and configured to calculate a movement of theplurality of joints in response to the reconfiguration command so thatthe calculated velocities of the joints are within a null-space of theJacobian. The system includes an input device for receiving areconfiguration command to move a first set of joints of the pluralityof joints with a desired reconfiguration movement while the end effectoris in the desired state.

A further understanding of the nature and advantages of the presentinvention will become apparent by reference to the remaining portions ofthe specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an overhead view of a robotic surgical system in accordancewith embodiments of the present invention, the robotic surgical systemhaving a surgical station with a plurality of robotic manipulators forrobotically moving surgical instruments having surgical end effectors atan internal surgical site within a patient.

FIG. 1B diagrammatically illustrates the robotic surgical system of FIG.1A.

FIG. 2 is a perspective view illustrating a master surgeon console orworkstation for inputting surgical procedure commands in the surgicalsystem of FIG. 1A, the console including a processor for generatingmanipulator command signals in response to the input commands.

FIG. 3 is a perspective view of the electronics cart of FIG. 1A.

FIG. 4 is a perspective view of a patient side cart having fourmanipulator arms.

FIGS. 5A-5D show an example manipulator arm.

FIGS. 6A-6B show an example manipulator arm in the pitch forwardconfiguration and pitch back configurations, respectively.

FIG. 6C shows a graphical representation of the range of motion of thesurgical instrument tool tip of an example manipulator arm, including acone of silence or conical tool access limit zone in each of the pitchforward and pitch back configurations.

FIG. 7A shows example manipulator arms having a proximal revolute jointthat revolves the manipulator arm about an axis of a proximal revolutejoint.

FIG. 7B shows an example manipulator arm and the associated range ofmotion and cone of silence, the example manipulator arm having aproximal revolute joint that revolves the manipulator arm around an axisof a proximal revolute joint the movement of which can be used tomitigate the depicted cone of silence.

FIG. 8 shows an example manipulator arm having a revolute joint near thedistal instrument holder.

FIG. 9 shows an example manipulator arm having a revolute joint near thedistal instrument holder that revolves or twists the instrument holderabout the joint axis.

FIGS. 10A-10C show sequential views of an example manipulator arm havinga revolute joint near a distal instrument holder as the joint is movedthroughout its range of joint movement.

FIGS. 11A-11B show the revolved profile of an example manipulator armhaving a distal revolute joint when the angular displacement of thejoint is 0° versus an angular displacement of 90°, respectively.

FIGS. 12A-12D and 13A-13C show example manipulator arms having aproximal joint that translates a proximal joint supporting themanipulator arm about a path of the joint.

FIGS. 14A-14B graphically represent the relationship between thenull-space and the null-perpendicular-space of the Jacobian of anexample manipulator assembly.

FIGS. 15A-15B illustrate reconfiguration of an example manipulatorassembly for a given end effector position.

FIGS. 16A-16B illustrate an example manipulator for a given remotecenter location at which an associated instrument shaft pivots.

FIGS. 17A-17C illustrate three examples of manipulation command inputsin accordance with many embodiments.

FIGS. 18A-18B are simplified block diagram representing methods inaccordance with many embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally provides improved surgical and roboticdevices, systems, and methods. The invention is particularlyadvantageous for use with surgical robotic systems in which a pluralityof surgical tools or instruments will be mounted on and moved by anassociated plurality of robotic manipulators during a surgicalprocedure. The robotic systems will often comprise telerobotic,telesurgical, and/or telepresence systems that include processorsconfigured as master-slave controllers. By providing robotic systemsemploying processors appropriately configured to move manipulatorassemblies with articulated linkages having relatively large numbers ofdegrees of freedom, the motion of the linkages can be tailored for workthrough a minimally invasive access site. The large number of degrees offreedom allows a system operator, or an assistant, to reconfigure thelinkages of the manipulator assemblies while maintaining the desired endeffector state, optionally in preparation for surgery and/or whileanother use maneuvers the end effector during a surgical procedure.

The robotic manipulator assemblies described herein will often include arobotic manipulator and a tool mounted thereon (the tool oftencomprising a surgical instrument in surgical versions), although theterm “robotic assembly” will also encompass the manipulator without thetool mounted thereon. The term “tool” encompasses both general orindustrial robotic tools and specialized robotic surgical instruments,with these later structures often including an end effector that issuitable for manipulation of tissue, treatment of tissue, imaging oftissue, or the like. The tool/manipulator interface will often be aquick disconnect tool holder or coupling, allowing rapid removal andreplacement of the tool with an alternate tool. The manipulator assemblywill often have a base which is fixed in space during at least a portionof a robotic procedure, and the manipulator assembly may include anumber of degrees of freedom between the base and an end effector of thetool. Actuation of the end effector (such as opening or closing of thejaws of a gripping device, energizing an electrosurgical paddle, or thelike) will often be separate from, and in addition to, these manipulatorassembly degrees of freedom.

The end effector will typically move in the workspace with between twoand six degrees of freedom. As used herein, the term “position”encompasses both location and orientation. Hence, a change in a positionof an end effector (for example) may involve a translation of the endeffector from a first location to a second location, a rotation of theend effector from a first orientation to a second orientation, or acombination of both. When used for minimally invasive robotic surgery,movement of the manipulator assembly may be controlled by a processor ofthe system so that a shaft or intermediate portion of the tool orinstrument is constrained to a safe motion through a minimally invasivesurgical access site or other aperture. Such motion may include, forexample, axial insertion of the shaft through the aperture site into asurgical workspace, rotation of the shaft about its axis, and pivotalmotion of the shaft about a pivot point adjacent the access site.

Many of the example manipulator assemblies described herein have moredegrees of freedom than are needed to position and move an end effectorwithin a surgical site. For example, a surgical end effector that can bepositioned with six degrees of freedom at an internal surgical sitethrough a minimally invasive aperture may in some embodiments have ninedegrees of freedom (six end effector degrees of freedom—three forlocation, and three for orientation—plus three degrees of freedom tocomply with the access site constraints), but may have ten or moredegrees of freedom. Highly configurable manipulator assemblies havingmore degrees of freedom than are needed for a given end effectorposition can be described as having or providing sufficient degrees offreedom to allow a range of joint states for an end effector position ina workspace. For example, for a given end effector position, themanipulator assembly may occupy (and be driven between) any of a rangeof alternative manipulator linkage positions. Similarly, for a given endeffector velocity vector, the manipulator assembly may have a range ofdiffering joint movement speeds for the various joints of themanipulator assembly within the null-space of the Jacobian.

The invention provides robotic linkage structures which are particularlywell suited for surgical (and other) applications in which a wide rangeof motion is desired, and for which a limited dedicated volume isavailable due to the presence of other robotic linkages, surgicalpersonnel and equipment, and the like. The large range of motion andreduced volume needed for each robotic linkage may also provide greaterflexibility between the location of the robotic support structure andthe surgical or other workspace, thereby facilitating and speeding upsetup.

The term “state” of a joint or the like will often herein refer to thecontrol variables associated with the joint. For example, the state ofan angular joint can refer to the angle defined by that joint within itsrange of motion, and/or to the angular velocity of the joint. Similarly,the state of an axial or prismatic joint may refer to the joint's axialposition, and/or to its axial velocity. While many of the controllersdescribed herein comprise velocity controllers, they often also havesome position control aspects. Alternative embodiments may relyprimarily or entirely on position controllers, acceleration controllers,or the like. Many aspects of control system that can be used in suchdevices are more fully described in U.S. Pat. No. 6,699,177, the fulldisclosure of which is incorporated herein by reference. Hence, so longas the movements described are based on the associated calculations, thecalculations of movements of the joints and movements of an end effectordescribed herein may by performed using a position control algorithm, avelocity control algorithm, a combination of both, and/or the like.

In certain embodiments, the tool of an example manipulator arm pivotsabout a pivot point adjacent a minimally invasive aperture. The systemmay utilize a hardware remote center, such as the remote centerkinematics described in U.S. Pat. No. 6,786,896, the contents of whichare incorporated herein in their entirety. Such systems may utilize adouble parallelogram linkage which constrains movement of the linkagessuch that the shaft of the instrument supported by the manipulatorpivots about a remote center point. Alternative mechanically constrainedremote center linkage systems are known and/or may be developed in thefuture. Surprisingly, work in connection with the present inventionindicates that remote center linkage systems may benefit from highlyconfigurable kinematic architectures. In particular when a surgicalrobotic system has a linkage that allows pivotal motion about two axesintersecting at or near a minimally invasive surgical access site, thespherical pivotal motion may encompass the full extent of a desiredrange of motion within the patient, but may still suffer from avoidabledeficiencies (such as being poorly conditioned, being susceptible toarm-to-arm or arm-to-patient contact outside the patient, and/or thelike). At first, adding one or more additional degrees of freedom thatare also mechanically constrained to pivotal motion at or near theaccess site may appear to offer few or any improvements in the range ofmotion. Nonetheless, such joints can provide significant advantages byallowing the overall system to be configured in or driven toward acollision-inhibiting pose, by further extending the range of motion forother surgical procedures, and the like. In some embodiments, the systemmay utilize software to achieve a remote center, such as described inU.S. Pat. No. 8,004,229, the entire contents of which are incorporatedherein by reference. In a system having a software remote center, theprocessor calculates movement of the joints so as to pivot anintermediate portion of the instrument shaft about a pivot pointdetermined, as opposed to a mechanical constraint. By having thecapability to compute software pivot points, different modescharacterized by the compliance or stiffness of the system can beselectively implemented. More particularly, different system modes overa range of pivot points/centers (e.g., moveable pivot points, passivepivot points, fixed/rigid pivot point, soft pivot points) can beimplemented as desired.

Despite the many advantages of a robotic surgical system having multiplehighly configurable manipulators, since the manipulators include arelatively large number of joints and links between the base andinstrument, manual positioning of the links can be challenging andcomplicated. Even when the manipulator structure is balanced so as toavoid gravitational effects, attempting to align each of the joints inan appropriate arrangement or to reconfigure the manipulator as desiredcan be difficult, time consuming, and may involve significant trainingand/or skill. The challenges can be even greater when the links of themanipulator are not balanced about the joints, such that positioningsuch a highly configurable structures in an appropriate configurationbefore or during surgery can be a struggle due to the manipulator armlength and the passive and limp design in many surgical systems. Thepresent invention allows a user, such as a physician's assistant, toquickly and easily reconfigure the manipulator arm, while maintainingthe desired end effector state, optionally even during movement of theend effector during a surgical procedure. In some embodiments, themanipulation and reconfiguration input can come from the same person(e.g. a user at the surgeon's console or the patient side cart).

Embodiments of the invention may include a user input that is configuredto take advantage of the degrees of freedom of a manipulator structure.Rather than manually reconfiguring the manipulator, the inputfacilitates use of driven joints of the kinematic linkage to reconfigurethe manipulator structure in response to entry of a reconfigurationcommand by a user. In certain embodiments, the user input for receivingthe reconfiguration command is incorporated into and/or disposed nearthe manipulator arm. The input may comprise a centralized input deviceto facilitate reconfiguration of one or more joints, such as a clusterof buttons on the patient side cart or a joystick. Typically, the inputdevice for receiving the reconfiguration command is separate from theinput for receiving a manipulation command to effect movement of the endeffector. A controller of the surgical system may include a processorwith readable memory having joint controller programming instructions orcode recorded thereon that allows the processor to derive suitable jointcommands for driving the joints recorded thereon so as to allow thecontroller to effect the desired reconfiguration in response to entry ofthe reconfiguration command.

In the following description, various embodiments of the presentinvention will be described. For purposes of explanation, specificconfigurations and details are set forth in order to provide a thoroughunderstanding of the embodiments. However, it will also be apparent toone skilled in the art that the present invention may be practicedwithout the specific details. Furthermore, well-known features may beomitted or simplified in order not to obscure the embodiment beingdescribed.

Referring now to the drawings, in which like reference numeralsrepresent like parts throughout the several views, FIG. 1A is anoverhead view illustration of a Minimally Invasive Robotic Surgical(MIRS) system 10, in accordance with many embodiments, for use inperforming a minimally invasive diagnostic or surgical procedure on aPatient 12 who is lying down on an Operating table 14. The system caninclude a Surgeon's Console 16 for use by a surgeon 18 during theprocedure. One or more Assistants 20 may also participate in theprocedure. The MIRS system 10 can further include a Patient Side Cart 22(surgical robot) and an Electronics Cart 24. The Patient Side Cart 22can manipulate at least one removably coupled tool assembly 26(hereinafter simply referred to as a “tool”) through a minimallyinvasive incision in the body of the Patient 12 while the surgeon 18views the surgical site through the Console 16. An image of the surgicalsite can be obtained by an endoscope 28, such as a stereoscopicendoscope, which can be manipulated by the Patient Side. Cart 22 so asto orient the endoscope 28. The Electronics Cart 24 can be used toprocess the images of the surgical site for subsequent display to thesurgeon 18 through the Surgeon's Console 16. The number of surgicaltools 26 used at one time will generally depend on the diagnostic orsurgical procedure and the space constraints within the operating roomamong other factors. If it is necessary to change one or more of thetools 26 being used during a procedure, an Assistant 20 may remove thetool 26 from the Patient Side Cart 22, and replace it with another tool26 from a tray 30 in the operating room.

FIG. 1B diagrammatically illustrates a robotic surgery system 50 (suchas MIRS system 10 of FIG. 1A). As discussed above, a Surgeon's Console52 (such as Surgeon's Console 16 in FIG. 1A) can be used by a surgeon tocontrol a Patient Side Cart (Surgical Robot) 54 (such as Patent SideCart 22 in FIG. 1A) during a minimally invasive procedure. The PatientSide Cart 54 can use an imaging device, such as a stereoscopicendoscope, to capture images of the procedure site and output thecaptured images to an Electronics Cart 56 (such as the Electronics Cart24 in FIG. 1A). As discussed above, the Electronics Cart 56 can processthe captured images in a variety of ways prior to any subsequentdisplay. For example, the Electronics Cart 56 can overlay the capturedimages with a virtual control interface prior to displaying the combinedimages to the surgeon via the Surgeon's Console 52. The Patient SideCart 54 can output the captured images for processing outside theElectronics Cart 56. For example, the Patient Side Cart 54 can outputthe captured images to a processor 58, which can be used to process thecaptured images. The images can also be processed by a combination theElectronics Cart 56 and the processor 58, which can be coupled togetherso as to process the captured images jointly, sequentially, and/orcombinations thereof. One or more separate displays 60 can also becoupled with the processor 58 and/or the Electronics Cart 56 for localand/or remote display of images, such as images of the procedure site,or other related images.

FIG. 2 is a perspective view of the Surgeon's Console 16. The Surgeon'sConsole 16 includes a left eye display 32 and a right eye display 34 forpresenting the surgeon 18 with a coordinated stereo view of the surgicalsite that enables depth perception. The Console 16 further includes oneor more input control devices 36, which in turn cause the Patient SideCart 22 (shown in FIG. 1A) to manipulate one or more tools. The inputcontrol devices 36 can provide the same degrees of freedom as theirassociated tools 26 (shown in FIG. 1A) so as to provide the surgeon withtelepresence, or the perception that the input control devices 36 areintegral with the tools 26 so that the surgeon has a strong sense ofdirectly controlling the tools 26. To this end, position, force, andtactile feedback sensors (not shown) may be employed to transmitposition, force, and tactile sensations from the tools 26 back to thesurgeon's hands through the input control devices 36.

The Surgeon's Console 16 is usually located in the same room as thepatient so that the surgeon may directly monitor the procedure, bephysically present if necessary, and speak to an Assistant directlyrather than over the telephone or other communication medium. However,the surgeon can be located in a different room, a completely differentbuilding, or other remote location from the Patient allowing for remotesurgical procedures.

FIG. 3 is a perspective view of the Electronics Cart 24. The ElectronicsCart 24 can be coupled with the endoscope 28 and can include a processorto process captured images for subsequent display, such as to a surgeonon the Surgeon's Console, or on another suitable display located locallyand/or remotely. For example, where a stereoscopic endoscope is used,the Electronics Cart 24 can process the captured images so as to presentthe surgeon with coordinated stereo images of the surgical site. Suchcoordination can include alignment between the opposing images and caninclude adjusting the stereo working distance of the stereoscopicendoscope. As another example, image processing can include the use ofpreviously determined camera calibration parameters so as to compensatefor imaging errors of the image capture device, such as opticalaberrations.

FIG. 4 shows a Patient Side Cart 22 having a plurality of manipulatorarms, each supporting a surgical instrument or tool 26 at a distal endof the manipulator arm. The Patient Side Cart 22 shown includes fourmanipulator arms 100 which can be used to support either a surgical tool26 or an imaging device 28, such as a stereoscopic endoscope used forthe capture of images of the site of the procedure. Manipulation isprovided by the robotic manipulator arms 100 having a number of roboticjoints. The imaging device 28 and the surgical tools 26 can bepositioned and manipulated through incisions in the patient so that akinematic remote center is maintained at the incision so as to minimizethe size of the incision. Images of the surgical site can include imagesof the distal ends of the surgical instruments or tools 26 when they arepositioned within the field-of-view of the imaging device 28.

Regarding surgical tool 26, a variety of alternative robotic surgicaltools or instruments of different types and differing end effectors maybe used, with the instruments of at least some of the manipulators beingremoved and replaced during a surgical procedure. Several of these endeffectors, including DeBakey Forceps, microforceps, Potts scissors, andclip applier include first and second end effector elements which pivotrelative to each other so as to define a pair of end effector jaws.Other end effectors, including scalpel and electrocautery probe have asingle end effector element. For instruments having end effector jaws,the jaws will often be actuated by squeezing the grip members of handle.Single end effector instruments may also be actuated by gripping of thegrip members, for example, so as to energize an electrocautery probe.

The elongate shaft of instrument 26 allow the end effectors and thedistal end of the shaft to be inserted distally into a surgical worksitethrough a minimally invasive aperture, often through an abdominal wallor the like. The surgical worksite may be insufflated, and movement ofthe end effectors within the patient will often be effected, at least inpart, by pivoting of the instrument 26 about the location at which theshaft passes through the minimally invasive aperture. In other words,manipulators 100 will move the proximal housing of the instrumentoutside the patient so that shaft extends through a minimally invasiveaperture location so as to help provide a desired movement of endeffector. Hence, manipulators 100 will often undergo significantmovement outside patient P during a surgical procedure.

Exemplary manipulator arms in accordance with many embodiments of thepresent invention can be understood with reference to FIGS. 5A-13C. Asdescribed above, a manipulator arm generally supports a distalinstrument or surgical tool and effects movements of the instrumentrelative to a base. As a number of different instruments havingdiffering end effectors may be sequentially mounted on each manipulatorduring a surgical procedure (typically with the help of a surgicalassistant), a distal instrument holder will preferably allow rapidremoval and replacement of the mounted instrument or tool. As can beunderstood with reference to FIG. 4, manipulators are proximally mountedto a base of the patient side cart. Typically, the manipulator armincludes a plurality of linkages and associated joints extending betweenthe base and the distal instrument holder. In one aspect, an examplemanipulator includes a plurality of joints having redundant degrees offreedom such that the joints of the manipulator arm can be driven into arange of differing configurations for a given end effector position.This may be the case for any of the embodiments of manipulator armsdisclosed herein.

In certain embodiments, such as shown for example in FIG. 5A, an examplemanipulator arm includes a proximal revolute joint J1 that rotates abouta first joint axis so as to revolve the manipulator arm distal of thejoint about the joint axis. In some embodiments, revolute joint J1 ismounted directly to the base, while in other embodiments, joint J1 maybe mounted to one or more movable linkages or joints. The joints of themanipulator, in combination, have redundant degrees of freedom such thatthe joints of the manipulator arm can be driven into a range ofdiffering configurations for a given end effector position. For example,the manipulator arm of FIGS. 5A-5D may be maneuvered into differingconfigurations while the distal member 511 (such as a cannula throughwhich the tool 512 or instrument shaft extends) supported within theinstrument holder 510 maintains a particular state and may include agiven position or velocity of the end effector. Distal member 511 istypically a cannula through which the tool shaft 512 extends, and theinstrument holder 510 is typically a carriage (shown as a brick-likestructure that translates on a spar) to which the instrument attachesbefore extending through the cannula 511 into the body of the patientthrough the minimally invasive aperture.

Describing the individual links of manipulator arm 500 of FIGS. 5A-5Dalong with the axes of rotation of the joints connecting the links asillustrated in FIG. 5A-5D, a first link 504 extends distally from apivotal joint J2 which pivots about its joint axis and is coupled torevolute joint J1 which rotates about its joint axis. Many of theremainder of the joints can be identified by their associated rotationalaxes, as shown in FIG. 5A. For example, a distal end of first link 504is coupled to a proximal end of a second link 506 at a pivotal joint J3that pivots about its pivotal axis, and a proximal end of a third link508 is coupled to the distal end of the second link 506 at a pivotaljoint J4 that pivots about its axis, as shown. The distal end of thethird link 508 is coupled to instrument holder 510 at pivotal joint J5.Typically, the pivotal axes of each of joints J2, J3, J4, and J5 aresubstantially parallel and the linkages appear “stacked” when positionednext to one another, as shown in FIG. 5D, so as to provide a reducedwidth w of the manipulator arm and improve patient clearance duringmaneuvering of the manipulator assembly. In certain embodiments, theinstrument holder also includes additional joints, such as a prismaticjoint J6 that facilitates axial movement of instrument 306 through theminimally invasive aperture and facilitates attachment of the instrumentholder to a cannula through which the instrument is slidably inserted.

The distal member or cannula 511 through which the tool 512 extends mayinclude additional degrees of freedom distal of instrument holder 510.Actuation of the degrees of freedom of the instrument will often bedriven by motors of the manipulator, and alternative embodiments mayseparate the instrument from the supporting manipulator structure at aquickly detachable instrument holder/instrument interface so that one ormore joints shown here as being on the instrument are instead on theinterface, or vice versa. In some embodiments, cannula 511 includes arotational joint J7 (not shown) near or proximal of the insertion pointof the tool tip or the pivot point PP, which generally is disposed atthe site of a minimally invasive aperture. A distal wrist of theinstrument allows pivotal motion of an end effector of surgical tool 512about instrument joints axes of one or more joints at the instrumentwrist. An angle between end effector jaw elements may be controlledindependently of the end effector location and orientation.

The range of motion of an example manipulator assembly can beappreciated by referring to FIGS. 6A-6C. During a surgical procedure, anexample manipulator arm can be maneuvered into a pitch forwardconfiguration, as shown in FIG. 6A, or into a pitch back configuration,as shown in FIG. 6B, as needed to access particular patient tissueswithin a surgical workspace. A typical manipulator assembly includes anend effector that can pitch forwards and backwards about an axis by atleast ±60 degrees, preferably by about ±75 degrees, and can also yawabout an axis by ±80 degrees. Although this aspect allows for increasedmaneuverability of the end effector with the assembly, there may beconfigurations in which movement of the end effector may be limited,particularly when the manipulator arm is in the full pitch forward orfull pitch back configuration as in FIGS. 6A and 6B. In one embodiment,the manipulator arm has a Range of Motion (ROM) of (+/−75 deg) for theouter pitch, and (+/−300 deg) for the outer yaw joints, respectively. Insome embodiments, the ROM may be increased for the outer pitch toprovide a ROM larger than (+/−90 deg) in which case the “cone ofsilence” could be made to disappear entirely, although generally theinner sphere associated with insertion limitations would remain. It isappreciated that various embodiments may be configured to have increasedor decreased ROM, that the above noted ROMs are provided forillustrative purposed, and further that the invention is not limited tothe ROMs described herein.

FIG. 6C graphically represents the overall range of motion and workspaceof the tool tip of the example manipulator of FIGS. 5A-5B. Although theworkspace is shown as hemisphere, it may also be represented as a spheredepending on the range of motion and configuration of one or morerevolute joints of the manipulator, such as joint J1. As shown, thehemisphere in FIG. 6C includes a central, small spherical void as wellas two conical voids. The voids represent the areas in which movement ofthe tool tip may be impossible due to mechanical constraints orunfeasible due to extremely high joint velocities that make movement ofthe end effector difficult or slow. For these reasons, the conical voidare referred to as the “cone of silence.” In some embodiments, themanipulator arm may reach a singularity at a point within the cone.Since movement of the manipulator within or near the cone of silence maybe impaired, it can be difficult to move the manipulator arm away fromthe cone of silence without manually moving one or more links of themanipulator to reconfigure the linkages and joints of the manipulator,which often requires an alternative operating mode and delays thesurgical procedure.

Movement of the instrument shaft into or near these conical portionstypically occurs when the angle between distal linkages in themanipulator is relatively small. Such configurations can be avoided byreconfiguring the manipulator to increase the angles between linkages(so that the linkages are moved into a more orthogonal position relativeto each other). For example, in the configurations shown in FIGS. 6A and6B, when the angle between the distal most link and the instrumentholder (angle a) becomes relatively small movement of the manipulatormay become more difficult. Depending on the range of joint movements inthe remaining joints in various embodiments, when the angle betweencertain linkages decreases, movement of the manipulator may be inhibitedand in some cases, the manipulator arm may no longer be redundant. Amanipulator configuration in which the instrument shaft nears theseconical portions, or in which the angles between linkages are relativelylow is said to be “poorly conditioned” such that maneuverability anddexterity of the manipulator arm is limited. It is desirable that themanipulator be “well-conditioned” so as to maintain dexterity and rangeof movement. In one aspect, the present invention allows a user to avoidmovement of the instrument shaft near the above described conicalportions by simply entering a command to reconfigure the manipulator asdesired, even during movement of the end effector in a surgicalprocedure. This aspect is particularly useful should the manipulator,for whatever reason, become “poorly conditioned.”

While the embodiments of the manipulator described above may be utilizedin the present invention, some embodiments may include additionaljoints, which may also be used to improve dexterity and the conditioningof the manipulator arm. For example, an example manipulator may includea revolute joint and/or linkage proximal of joint J1 which can be usedto revolve the manipulator arm of FIG. 5A, and its associated cone ofsilence, about, an axis of the revolute joint so as to reduce oreliminate the cone of silence. In another embodiment, the examplemanipulator may also include a distal pivotal joint that pivots theinstrument holder about an axis substantially perpendicular to joint J5,thereby offsetting the tool tip so as to further reduce the cone ofsilence and improve the range of movement of the surgical tool. In stillanother embodiment, a proximal joint of the manipulator arm, such as J1,may be movably mounted on the base, so as to move or shift the cone ofsilence as needed and improve the range of motion of the manipulatortool tip. The use and advantages of such additional joints can beunderstood by referring to FIGS. 7A-13C, which illustrate examples ofsuch joints, which may each be used independent of one another or usedin combination, in any of the example manipulator arms described herein.

FIGS. 7A-7B illustrate an additional redundant joint for use withexample manipulator arms—a first joint coupling a proximal portion ofthe manipulator arm to the base. The first joint is a proximal revolutejoint TJ that revolves the manipulator arm about a joint axis of jointTJ. The proximal revolute TJ includes a link 501 that offsets joint J1from the proximal revolute TJ by a pre-detemined distance or angle. Thelink 501 can be a curved linkage, as shown in FIG. 7A, or a linear orangled linkage, as shown in FIG. 7B. Typically, the joint axis of thejoint TJ is aligned with the remote center RC or insertion point of thetool tip, as shown in each of FIG. 7A. In an example embodiment, thejoint axis of joint TJ passes through the remote center, as does eachother revolute joint axis in the manipulator arm, to prevent motion atthe body wall and can therefore be moved during surgery. The axis ofjoint TJ is coupled to a proximal portion of the arm so it can be usedto change the position and orientation of the back of the arm. Ingeneral, redundant axes, such as this, allow the instrument tip tofollow the surgeon's commands while simultaneously avoiding collisionswith other arms or patient anatomy. In one aspect, the proximal revoluteTJ is used solely to change the mounting angle of the manipulator withrespect to the floor. This angle is important in order to 1) avoidcollisions with external patient anatomy and 2) reach anatomy inside thebody. Typically, the angle a between the proximal link of themanipulator attached to the proximal revolute joint TJ and the axis ofthe proximal revolute is about 15 degrees.

FIG. 7B illustrates the relationship of the proximal revolute joint TJand its associated joint axis and the cone of silence in an examplemanipulator arm. The joint axis of the proximal revolute joint TJ maypass through the cone of silence or may be completely outside of thecone of silence. By revolving the manipulator arm about the axis of theproximal revolute TJ, the cone of silence can be reduced (in anembodiment where the joint TJ axis passes through the cone of silence),or can be effectively eliminated (in an embodiment where the proximalrevolute joint axis extends completely outside the cone of silence). Thedistance and angle of the link 501 determines the position of the jointTJ axis relative to the cone of silence.

FIG. 8 illustrates another type of redundant joint for use with examplemanipulator arms, a distal revolute joint TWJ coupling the instrumentholder 510 to a distal link of the manipulator arm 508. The distalrevolute joint TWJ allows the system to twist the instrument holder 510about the joint axis, which typically passes through the remote centeror insertion point. Ideally, the revolute joint is located distally onthe arm and is therefore particularly well suited to moving theorientation of the insertion axis. The addition of this redundant axisallows the manipulator to assume multiple positions for any singleinstrument tip position. In general, redundant axes, such as this, allowthe instrument tip to follow the surgeon's commands while simultaneouslyavoiding collisions with other arms or patient anatomy. Because thedistal revolute joint TWJ has the ability to move the insertion axiscloser to the yaw axis, it is able to increase arm pitch back range ofmotion.

of FIG. 8. The relationship between the axis of the distal revolutejoint TWJ, the yaw axis of J1 and the insertion axis of tool tip isshown in FIG. 9. FIGS. 10A-10C show the sequential movement of the TWJand how it shifts the insertion axis of tool tip from side to side.

Another advantage of the distal revolute joint TWJ is that it may reducethe patient clearance cone, which is the swept volume of the distalportion of the manipulator arm proximal of the insertion point whichmust clear the patient to avoid collision between the patient and theinstrument holder or distal linkages of the manipulator arm. FIG. 11Aillustrates the patient clearance cone of the proximal portion of themanipulator arm while the angular displacement of the distal revolutejoint remains at 0°. FIG. 11B illustrates the reduced patient clearancecone of the proximal portion of the manipulator arm while the distalrevolute joint is shown having an angular displacement of 90° about itsaxis. Thus, in procedures having minimal patient clearance near theinsertion point, use of the joint TWJ in accordance with the presentinvention may provide additional clearance while maintaining the remotecenter location or the position of the end effector as desired.

FIGS. 12A-13C illustrate another type of redundant joint for use withexample manipulator arms, a proximal joint that translates or revolvesthe manipulator arm about an axis. In certain embodiments, this proximaltranslatable joint translates a proximal joint of the manipulator, suchas joint J1 or TJ, along a path so as to reduce or eliminate the cone ofsilence by shifting or rotating the range of motion of the manipulatorarm to provide for better conditioning and improved maneuverability ofthe manipulator arm. The translatable joint may include a circular path,such as shown in joint HJ1 in FIGS. 12A-12D, or may include asemi-circular or arcuate path, such as shown in FIGS. 13A-13C.Generally, the joint revolves the manipulator arm about an axis of thetranslatable joint that intersects with the remote center RC about whichthe shaft of the tool 512 extending through cannula 511 pivots. In theembodiment shown in FIGS. 12A-12D, this axis of HJ1 is a vertical axis,whereas in the embodiment shown in FIGS. 13A-13C the axis of HJ2 ishorizontal.

In example embodiments, the manipulator arm 500 may include any or allof the a proximal or distal revolute joint, a proximal translatablejoint and a parallelogram configuration of the distal linkages. Use ofany or all of these features provide additional redundant degrees offreedom and facilitate reconfiguration in accordance with the presentinvention so as to provide for a better “conditioned” manipulatorassembly by increasing the angles between linkages thereby improving thedexterity and motion of the manipulator. The increased flexibility ofthis example manipulator can also be used to optimize the kinematics ofthe manipulator linkage so as to avoid joint limits, singularities, andthe like.

In an example embodiment, the joint movements of the manipulator arecontrolled by driving one or more joints by a controller using motors ofthe system, the joints being driven according to coordinated and jointmovements calculated by a processor of the controller. Mathematically,the controller may perform at least some of the calculations of thejoint commands using vectors and/or matrices, some of which may haveelements corresponding to configurations or velocities of the joints.The range of alternative joint configurations available to the processormay be conceptualized as a joint space. The joint space may, forexample, have as many dimensions as the manipulator has degrees offreedom, and a particular configuration of the manipulator may representa particular point in the joint space, with each coordinatecorresponding to a joint state of an associated joint of themanipulator.

In an example embodiment, the system includes a controller in which acommanded position and velocity of a feature in the work-space, denotedhere as its Cartesian-coordinate space (referred to herein asCartesian-space), are inputs. The feature may be any feature on themanipulator or off the manipulator which can be used as a control frameto be articulated using control inputs. An example of a feature on themanipulator, used in many examples described herein, would be thetool-tip. Another example of a feature on the manipulator would be aphysical feature which is not on the tool-tip, but is a part of themanipulator, such as a pin or a painted pattern. An example of a featureoff the manipulator would be a reference point in empty space which isexactly a certain distance and angle away from the tool-tip. Anotherexample of a feature off the manipulator would be a target tissue whoseposition relative to the manipulator can be established. In all thesecases, the end effector is associated with an imaginary control framewhich is to be articulated using control inputs. However, in thefollowing, the “end effector” and the “tool tip” are used synonymously.Although generally, there is no closed form relationship which maps adesired Cartesian space end effector position to an equivalentjoint-space position, there is generally a closed form relationshipbetween the Cartesian space end effector and joint-space velocities. Thekinematic Jacobian is the matrix of partial derivatives of Cartesianspace position elements of the end effector with respect to joint spaceposition elements. In this way, the kinematic Jacobian captures thekinematic relationship between the end effector and the joints. In otherwords, the kinematic Jacobian captures the effect of joint motion on theend effector. The kinematic Jacobian (J) can be used to map joint-spacevelocities (dq/dt) to Cartesian space end effector velocities (dx/dt)using the relationship below:

dx/dt=J dq/dt

Thus, even when there is no closed-form mapping between input and outputpositions, mappings of the velocities can iteratively be used, such asin a Jacobian-based controller to implement a movement of themanipulator from a commanded user input, however a variety ofimplementations can be used. Although many embodiments include aJacobian-based controller, some implementations may use a variety ofcontrollers that may be configured to access the Jacobian of themanipulator arm to provide any of the features described herein.

One such implementation is described in simplified terms below. Thecommanded joint position is used to calculate the Jacobian (J). Duringeach time step (Δt) a Cartesian space velocity (dx/dt) is calculated toperform the desired move (dx_(des)/dt) and to correct for built updeviation (Δx) from the desired Cartesian space position. This Cartesianspace velocity is then converted into a joint-space velocity (dq/dt)using the pseudo-inverse of the Jacobian (J^(#)). The resultingjoint-space commanded velocity is then integrated to produce joint-spacecommanded position (q). These relationships are listed below:

dx/dt=dx _(des) /dt+kΔx  (1)

dq/dt=J ^(#) dx/dt  (2)

q_(i) =q ₋₁ +dq/dtΔt  (3)

The pseudo-inverse of the Jacobian (J) directly maps the desired tooltip motion (and, in some cases, a remote center of pivotal tool motion)into the joint velocity space. If the manipulator being used has moreuseful joint axes than tool tip degrees of freedom (up to six), (andwhen a remote center of tool motion is in use, the manipulator shouldhave an additional 3 joint axes for the 3 degrees of freedom associatedwith location of the remote center), then the manipulator is said to beredundant. A redundant manipulator's Jacobian includes a “null-space”having a dimension of at least one. In this context, the “null-space” ofthe Jacobian (N(J)) is the space of joint velocities whichinstantaneously achieves no tool tip motion (and when a remote center isused, no movement of the pivotal point location); and “null-motion” isthe combination, trajectory or path of joint positions which alsoproduces no instantaneous movement of the tool tip and/or location ofthe remote center. Incorporating or injecting the calculated null-spacevelocities into the control system of the manipulator to achieve thedesired reconfiguration of the manipulator (including anyreconfigurations described herein) changes above equation (2) to thefollowing:

dq/dt=dq _(perp) /dt+dq _(null) /dt  (4)

dq _(perp) /dt=J ^(#) dx/dt  (5)

dq _(null) /dt=(1−J ^(#) J)z=V _(n) V _(n) ^(T) z=V _(n)α  (6)

The joint velocity according to Equation (4) has two components: thefirst being the null-perpendicular-space component, the “purest” jointvelocity (shortest vector length) which produces the desired tool tipmotion (and when the remote center is used, the desired remote centermotion); and the second being the null-space component. Equations (2)and (5) show that without a null-space component, the same equation isachieved. Equation (6) starts with a traditional form for the null-spacecomponent on the left, and on the far right side, shows the form used inan example system, wherein (V_(n)) is the set of orthonormal basisvectors for the null-space, and (α) are the coefficients for blendingthose basis vectors. In some embodiments, α is determined by controlparameters, variables or setting, such as by use of knobs or othercontrol means, to shape or control the motion within the null-space asdesired.

FIG. 14A graphically illustrates the relationship between the null-spaceof the Jacobian and the null-perpendicular-space of the Jacobian of anexample manipulator arm. FIG. 14A shows a two-dimensional schematicshowing the null-space along the horizontal axis, and thenull-perpendicular-space along the vertical axis, the two axes beingorthogonal to one another. The diagonal vector represents the sum of avelocity vector in the null-space and a velocity vector in thenull-perpendicular-space, which is representative of Equation (4) above.

FIG. 14B graphically illustrates the relationship between the null-spaceand the null-motion manifold within a four-dimensional joint space,shown as the “null-motion manifold.” Each arrow (q1, q2, q3, and q4)represents a principal joint axis. The closed curve represents anull-motion manifold which is a set of joint-space positions thatinstantaneously achieves the same end effector position. For a givenpoint A on the curve, since the null-space is a space of jointvelocities that instantaneously produces no movement of the endeffector, the null-space is parallel to the tangent of the null-motionmanifold at point A.

FIGS. 15A-15B schematically illustrate an example manipulator 500 beforeand after reconfiguring of the manipulator arm by driving the joints ofthe manipulator within the null space. In FIG. 15A, in response to areconfiguration command entered by a user, the system drives the jointTJ counter-clockwise within the null-space for the given position of theend effector of instrument and according to the calculated movement ofthe remaining joints, the coordinated movements of the remaining jointswithin the null-space having been calculated by the system. Thenull-space joint velocities are injected into the system so as tomaintain the given state of the end effector, thereby enabling the userto reconfigure the manipulator as desired, even during movement of theend effector during a surgical procedure. In another aspect, the systemmay calculate the velocities of the joints within the null-space of theJacobian so as to effect the desired configuration while the structuraldesign of the manipulator arm maintains the remote center location, suchas in the embodiment shown in FIGS. 16A-16B.

In some embodiments, one or more joints of the manipulator arm may beconstrained such that the one or more joints are not driven within thenull-space to effect reconfiguration, however such joints may still bedriven within the null-perpendicular-space to effect a desired movementof the end effector. Alternatively, one or more joints, such as the aproximal revolute joint, may be constrained so that the one or morejoints are not driven to effect a desired movement of the end effector,but are driven to effect reconfiguration movement of the manipulator. Inother embodiments, the controller may be configured such that thevelocity of the joints driven within the null-space is limited or heldat a substantially constant speed for a duration of the reconfigurationcommand. In still other embodiments, the system may be configured suchthat the velocities of the joints within the null-space are scaledaccording to the joint location and/or configuration, or any number ofconditions. For example, a user may desire the proximal most joints bedriven with a higher velocity than the more distal joints in themanipulator arm during reconfiguration movement. Additionally, thesystem may be configured so as to maintain a position or state of anyone of the joints of the manipulator arm as desired.

In another aspect, the system may receive the reconfiguration commandfrom a system user in any number of ways. In certain embodiments, themanipulator includes an input device for receiving a reconfigurationcommand from a user. The input device may include one or more buttons ormechanisms for driving one or more joints as desired (or alternativelyfor moving one or more links) and may be disposed on the manipulatorarm, preferably in a location corresponding to the joint driven inresponse to activation of the device, such as in FIG. 17A.Alternatively, the system may include an input device having a clusterof buttons or mechanisms, each corresponding to a joint or linkage ofthe manipulator arm, such as that shown in the embodiment of FIG. 17B.This embodiment allows a user to reconfigure the arm from a centralizedlocation. The input device may also comprise a joystick, such as in FIG.17C, that may be operated to drive one or more joints and effectreconfiguration as desired. It is appreciated that the input device mayinclude any number of variations.

FIGS. 18A-18B illustrate methods of reconfiguring a manipulator assemblyof a robotic surgical system in accordance with many embodiments of thepresent invention. FIG. 18A shows a simplified schematic of the requiredblocks need to implement the general algorithms to control the patientside cart joint states, in relation to the equations discussed above.According to the method of FIG. 18A, the system: calculates the forwardkinematics of the manipulator arm; then calculates dx/dt using Equation(1), calculates dq_(perp)/dt using Equation (5), and then calculatesdq_(null)/dt from z which may depend on dq_(perp)/dt and the Jacobianusing Equation (6). From the calculated dq_(perp)/dt and dq_(null)/dt,the system then calculates dq/dt and q using Equations (4) and (3),respectively, thereby providing the movement by which the controller caneffect the desired reconfiguration of the manipulator while maintainingthe desired state of the end effector and/or location of the remotecenter.

FIG. 18B shows a block diagram of an example embodiment of the system.In response to a manipulation command, which commands a desired tool tipstate, the system determines the velocities of the tool tip and thestates of the joints from which the dq_(perp)/dt is calculated. Inresponse to receiving a reconfiguration command from a user, a processorcan use the determined tool tip and joint velocities (or the calculateddq_(perp)/dt) to calculate the dq_(null)/dt, after which the system addsthe velocities into the calculated dq/dt so as to drive the joint(s) ofthe system and effecting the desired movement (or state) of the endeffector and reconfiguration of the manipulator arm.

While the example embodiments have been described in some detail forclarity of understanding and by way of example, a variety ofadaptations, modifications, and changes will be obvious to those ofskill in the art. Hence, the scope of the present invention is limitedsolely by the appended claims.

What is claimed is:
 1. A robotic method comprising: providing amanipulator arm including a movable distal portion, a proximal portioncoupled to a base, and a plurality of joints between the distal portionand the base, the plurality of joints having sufficient degrees offreedom to allow a range of differing joint states of the plurality ofjoints for a given state of the distal portion; receiving areconfiguration command entered into a user input by a user while thedistal portion is in a desired state; driving a first set of joints ofthe plurality with a desired reconfiguration movement in response to thereconfiguration command; calculating a reconfiguration movement of oneor more of the joints of the plurality in response to thereconfiguration command so that the reconfiguration movement of thefirst set of joints combined with the calculated joint velocities arewithin a null-space of a Jacobian of the manipulator arm; and drivingthe one or more joints according to the calculated movement during thedriving of the first set of joints so as to maintain the desired stateof the distal portion.
 2. The method of claim 1, wherein the first setof joints comprises one or more joints of the manipulator arm.
 3. Therobotic method of claim 1, wherein the distal portion comprises or isconfigured to releasably support a surgical instrument having anelongate shaft extending distally to a surgical end effector, whereinthe instrument shaft pivots about a remote center during surgery, andwherein the calculated movement of the one or more joints is calculatedso as to maintain a position of the remote center during driving of thefirst set of joints.
 4. The robotic method of claim 3, furthercomprising: receiving a manipulation command to move the end effectorwith a desired end effector movement; calculating an end effectordisplacing movement of the joints to effect the desired end effectormovement; and driving the joints according to the end effectormanipulation command, wherein calculating the end effector displacingmovement of the joints further comprises calculating joint velocitieswithin a null-perpendicular-space of the Jacobian, thenull-perpendicular-space being orthogonal to the null-space.
 5. Therobotic method of claim 4, wherein a manipulation command is receivedwith an end effector input device from a first system operator, and thereconfiguration command is entered into the user input by a secondsystem operator.
 6. The robotic method of claim 4, wherein thereconfiguration command is input by a surgical assistant and aninterface of the user input is supported by a structure supporting thebase, and wherein the manipulation command is input into a surgeonconsole of the user interface, the surgeon console being movableindependently of the support structure.
 7. The robotic method of claim3, wherein the end effector displacing movement of the joints iscalculated so that the first set of joints are not driven.
 8. Therobotic method of claim 3, wherein the end effector displacing movementof the joints is calculated so that the first set of joints are notdriven to effect the desired end effector movement.
 9. The roboticmethod of claim 1, wherein the input received from the user comprises aduration of the desired reconfiguration movement, wherein the driving ofthe first set of joints comprises providing a substantially constantjoint articulation velocity of a first joint from the first set ofjoints, and wherein the reconfiguration movement is calculated toprovide a substantially constant speed of the first joint during theduration of the reconfiguration command.
 10. The robotic method of claim1, wherein the desired state of the distal portion comprises a distalportion position, orientation, and/or velocity relative to the base. 11.The robotic method of claim 1, wherein the manipulator arm is configuredto support a tool having an intermediate portion with the intermediateportion extending along an insertion axis distally of the proximalportion and an end effector at a distal end of the intermediate portion,wherein at least some of the joints mechanically constrain movement ofthe distal portion relative to the base such that the distal portion ofthe manipulator arm pivots about a remote center disposed along theinsertion axis to facilitate movement of the end effector at a worksite, and wherein the work site is accessed through an insertionopening.
 12. The robotic method of claim 11, wherein a plurality of thejoints comprise remote spherical center joints disposed distally of theproximal portion and proximally of the distal portion, wherein theremote spherical center joints are mechanically constrained so thatarticulation of the remote spherical center joints pivot the distalportion of the manipulator arm about first, second, and third remotecenter axes, the first, second, and third remote center axesintersecting the remote center.
 13. The robotic method of claim 11,wherein the proximal portion is mechanically constrained relative to thebase such that the distal portion of the manipulator arm pivots aboutthe remote center when the proximal portion moves.
 14. The roboticmethod of claim 11, wherein a first joint from the first set of jointscouples the proximal portion to the base, the first joint from the firstset of joints comprising a revolute joint that supports the distalportion of the manipulator arm such that joint movement of the revolutejoint pivots the distal portion of the manipulator arm about a pivotalaxis of the revolute joint, wherein the pivotal axis extends from therevolute joint and through the remote center so that the insertion axisof the manipulator arm moves along a distally tapered cone orientedtowards the remote center.
 15. The robotic method of claim 11, wherein afirst joint from the first set of joints couples the proximal portion tothe base so that the distal portion is moveable relative to the basealong a path, the path being arcuate or substantially circular such thatmovement of the proximal portion along the path pivots the insertionaxis of the distal portion of the manipulator arm at the remote center.16. The robotic method of claim 11, wherein an intermediate link isdisposed proximal of and adjacent to the distal portion with a firstjoint from the first set of joints therebetween, the first jointcomprising a revolute joint mechanically constraining movement of thedistal portion relative to the intermediate link to rotation about afirst joint axis, the first joint axis extending from the first jointdistally toward the intermediate portion so as to intersect theinsertion axis through the remote center.
 17. The robotic method ofclaim 1, wherein providing a manipulator arm comprises including adistal end effector supported by the distal portion and a series ofkinematically joined links extending between the proximal portion andthe distal end effector, wherein the proximal portion is coupled to thebase by a first joint from the first set of joints such that theproximal portion of the manipulator arm moves relative to the baseduring the reconfiguration movement of the links, and wherein the firstjoint comprises a revolute joint that supports the links of themanipulator arm such that joint movement of the revolute joint pivotsthe links of the manipulator arm about a pivotal axis of the revolutejoint, the pivotal axis extending from the revolute joint and throughthe remote center.
 18. A robotic method comprising: providing amanipulator arm configured to support a distal tool with a distal endeffector and an elongate intermediate portion disposed along aninsertion axis and supporting the end effector for manipulating the endeffector through a minimally invasive aperture, wherein the manipulatorarm has a proximal portion coupled to a base, and a plurality of joints,the plurality of joints having sufficient degrees of freedom to allow arange of joint states for a given end effector position, wherein atleast some of the joints comprise remote center joints mechanicallyconstrained to pivotal movement about a remote center along theinsertion axis and adjacent the minimally invasive aperture; driving afirst set of joints of the plurality of joints in response to areconfiguration command while the end effector is in a desired state;calculating a movement of the joints in response to the reconfigurationcommand so that the movement of the first set of joints and thecalculated velocities of the joints together are within a null-space ofthe Jacobian; and driving one or more of the remote center jointsaccording to the calculated movement while driving the first set ofjoints in response to the commanded movement so as to maintain thedesired end effector state.
 19. The robotic method of claim 18, furthercomprising constraining movement of the remote center joints with aparallelogram linkage system including: a parallelogram linkage basecoupled to the base for rotation about a first remote center axisintersecting the remote center; a first link having a first linkproximal end and a first link distal end, the first link proximal endcoupled to the parallelogram linkage base at a base joint, the firstlink distal end configured to support the tool; a second link having asecond link proximal end and a second link distal end, the second linkproximal end coupled to the first link distal end, the second linkdistal end configured to support the tool so that an insertion axis ofthe tool is constrained to rotation about a second remote center axisintersecting the remote center.
 20. The robotic method of claim 18,wherein the remote center joints constrain motion of the insertion axisto pivotal motion about the first and second remote center axesextending through the remote center, and wherein a first joint of thefirst set of joints is configured to constrain motion of the insertionaxis to rotation about a first remote center axis extending through theremote center.
 21. The robotic method of claim 18, further comprising:receiving a manipulation command from a user input to move the endeffector with a desired end effector movement; calculating an endeffector displacing movement of the joints; and driving the jointsaccording to the end effector manipulation command, wherein calculatingthe end effector displacing movement of the joints further comprisescalculating joint velocities within a null-perpendicular-space of theJacobian, the null-perpendicular-space being orthogonal to thenull-space.
 22. The robotic method of claim 21, wherein calculated endeffector displacing movement of the joints is calculated so that thefirst set of joints is not driven to effect the desired end effectormovement.
 23. The robotic method of claim 18, wherein calculatedreconfiguration movement of the joints is calculated so that themovement of a first joint from the first set of joints provides asubstantially constant speed of the first joint for a duration of thereconfiguration command.
 24. The robotic method of claim 21, wherein themanipulation command is received with an end effector input device froma first system operator, and wherein the reconfiguration command isreceived by a user input interface from a second system operator. 25.The robotic method of claim 18, wherein the proximal portion is coupledto the base by a joint of the plurality such that the proximal portionof the manipulator arm is moveable relative to the base while joints aredriven.
 26. The robotic method of claim 18, wherein a first joint fromthe first set of joints couples the proximal portion to the base, thefirst joint from the first set of joints comprising a revolute jointthat supports the remote center joints of the manipulator arm such thatjoint movement of the revolute joint pivots the remote center joints ofthe manipulator arm about a pivotal axis of the revolute joint, whereinthe pivotal axis extends from the revolute joint toward the remotecenter.
 27. The robotic method of claim 18, wherein a first joint fromthe first set of joints is configured to couple the remote center jointsto the tool, the first joint from the first set of joints comprising arevolute joint configured to support the tool such that joint movementof the revolute joint pivots the insertion axis about a pivotal axis ofthe revolute joint, wherein the pivotal axis extends from the revolutejoint toward the remote center.
 28. The robotic method of claim 26,wherein joint movement of the revolute joint pivots one or more jointsof the manipulator arm about a remote center.
 29. A robotic methodcomprising: providing a manipulator arm configured to support a distaltool with a distal end effector extended along an insertion axis througha minimally invasive aperture, a proximal portion of a proximal linkbeing coupled to a base, and a plurality of kinematically joined linksextending therebetween, some of the links comprising remote center linkscoupled together by remote center joints configured to mechanicallyconstrain movement of the insertion axis to rotation about first andsecond remote center axes traversing the insertion axis extendingthrough a remote center; moving a first link of the plurality of linksto effect a desired reconfiguration by driving one or more joints joinedto the first link in response to a reconfiguration command entered intoa user input device by a user, wherein driving of the one or more jointspivotally moves the insertion axis about a first joint axis, the firstjoint axis traversing the insertion axis extending through the remotecenter.
 30. The robotic method of claim 29, further comprising:receiving a manipulation command from a user input to move the endeffector with a desired end effector movement; calculating an endeffector displacing movement of the links; and driving the jointscoupling the plurality of links according to the end effectormanipulation command, wherein calculating the end effector displacingmovement of the joints further comprises calculating joint velocitieswithin a null-perpendicular-space of a Jacobian of the manipulator arm,the null-perpendicular-space being orthogonal to the null-space.
 31. Therobotic method of claim 30, wherein calculated end effector displacingmovement of the links is calculated so as to inhibit movement of thefirst link relative to the base.
 32. The robotic method of claim 29,wherein calculated reconfiguration movement of the joints is calculatedso that the movement of the first link provides a substantially constantspeed for a duration of the reconfiguration command.
 33. The roboticmethod of claim 30, wherein the reconfiguration command is input into apatient side cart of the user input interface and the manipulationcommand is input into a surgeon console of the user interface.
 34. Therobotic method of claim 30, wherein the reconfiguration command is inputinto a surgeon console of the user input interface and the manipulationcommand is input into the surgeon console.
 35. The robotic method ofclaim 30, wherein the reconfiguration command is input into a patientside cart of the user input interface and the manipulation command isinput into the patient side cart.
 36. The robotic method of claim 29,wherein the proximal portion is attached to the base such that movementof the proximal portion relative to the base is inhibited duringmovement of the links.
 37. The robotic method of claim 29, wherein ajoint coupling the proximal portion to the base is a revolute joint thatsupports the links of the manipulator arm such that movement of therevolute joint pivots one or more links of the manipulator arm about apivotal axis of the revolute joint, wherein the pivotal axis extendsfrom the revolute joint toward the remote center.
 38. The robotic methodof claim 37, wherein joint movement of the revolute joint pivots one ormore links of the manipulator arm about the remote center.
 39. Therobotic method of claim 29, wherein the joint coupling the proximalportion to the base is moveable relative to the base along a path thatis arcuate or substantially circular such that movement of the jointalong the path pivots one or more links of the manipulator arm about anaxis extending toward the remote center.
 40. A robotic systemcomprising: a manipulator arm configured for robotically moving a distalportion relative to a proximal base, the manipulator arm having aplurality of joints between the distal portion and a proximal portioncoupled to the base, the joints providing sufficient degrees of freedomto allow a range of joint states for a given state of the distalportion; an input device for receiving a reconfiguration command to movea first set of joints of the plurality of joints with a desiredreconfiguration movement; and a processor coupling the input device tothe manipulator arm, the processor configured to calculate a movement ofthe plurality of joints in response to the reconfiguration command sothat the commanded movement of the first set of joints together with thecalculated velocities of the joints are within a null-space of aJacobian of the manipulator arm, the processor configured to drive thejoints according to the calculated movement during the commandedmovement of the first set of joints so as to maintain a desired state ofthe distal portion during the reconfiguration movement.
 41. The systemof claim 40, wherein the first set of joints comprises one or morejoints of the manipulator arm.
 42. The robotic system of claim 40further comprising: an input device for receiving a manipulation commandto move the distal portion with a desired distal portion movement,wherein the processor is further configured to calculate a distalportion displacing movement of the joints in response to themanipulation command, wherein calculating the distal portion displacingmovement of the joints comprises calculating joint velocities within anull-perpendicular-space of the Jacobian, the null-perpendicular-spacebeing orthogonal to the null-space, and wherein the processor is furtherconfigured to drive the joints according to the calculated distalportion displacing movement of the joints so as to effect the desireddistal portion movement.
 43. The robotic system of claim 42, wherein theprocessor is configured to calculate joint movement so that the firstset of joints is not driven in calculating the distal portion displacingmovement of the joints.
 44. The robotic system of claim 42, wherein theprocessor is configured to calculate joint movement so that the firstset of joints is not driven to effect the distal portion displacingmovement of the joints in calculating the distal portion displacingmovement of the joints.
 45. The robotic system of claim 40, wherein theprocessor is configured to calculate joint movement so that movement ofa first joint of the first set of joints provides a substantiallyconstant speed of the first joint for a duration of the reconfigurationcommand.
 46. The robotic system of claim 40, wherein the input devicefor receiving the reconfiguration command is disposed on a portion ofthe manipulator arm such that entering a command using the input devicedrives an adjacent joint so as to move the portion of the manipulatorarm on which the input device is located.
 47. The robotic system ofclaim 40, wherein the input device for receiving the reconfigurationmanipulation command comprises a button cluster, wherein the buttoncluster comprises a plurality of buttons, each button corresponding to adifferent joint of the plurality.
 48. The robotic system of claim 40,wherein the input device for receiving the reconfiguration manipulationcommand comprises a joystick such that the plurality of joints areselectively driveable by movement of the joystick.
 49. The roboticsystem of claim 42, wherein the user interface comprises a surgeonconsole and a patient side cart, wherein the manipulation input and thereconfiguration input are configured such that both are disposed on thepatient side cart, both are disposed on the surgeon console, or themanipulation input is disposed on the surgeon console while thereconfiguration input is disposed on the patient side cart.
 50. Therobotic system of claim 40, wherein a proximal portion of themanipulator arm is coupled to the base by a first joint from the firstset of joints.
 51. The robotic system of claim 40, wherein a proximalportion of the manipulator arm is coupled to the base by a joint of theplurality such that the proximal portion of the manipulator arm ismoveable relative to the base while joints are driven according to thecalculated reconfiguration movement.
 52. The robotic system of claim 50,wherein the joint coupling the proximal portion to the base is arevolute joint that supports the joints of the manipulator arm such thatjoint movement of the revolute joint pivots one or more joints of themanipulator arm about a pivotal axis of the revolute joint, the pivotalaxis extending from the revolute joint through the distal portion. 53.The robotic system of claim 52, wherein joint movement of the revolutejoint pivots one or more joints of the manipulator arm about an axisoriented towards the remote center.
 54. The robotic system of claim 51,wherein the joint coupling the proximal portion to the base is moveablerelative to the base along an arcuate or substantially circular suchthat movement of the joint along the path pivots one or more joints ofthe manipulator arm about an axis extending through the remote center.55. A robotic system comprising: a manipulator arm for roboticallymoving a distal end effector relative to a proximal base, themanipulator arm comprising a plurality of kinematically joined links,the links having sufficient degrees of freedom to allow motion within anull-space of a Jacobian of the manipulator arm for a given state of theend effector; an input device for receiving a reconfiguration command tomove at least one link of the plurality with a desired reconfigurationmovement; a processor coupling the reconfiguration input to themanipulator arm, the processor being configured to calculate movement ofthe plurality of links in response to the reconfiguration command sothat the reconfiguration movement of the at least one link and thecalculated movement of the links are within a null-space of theJacobian; and wherein the processor is configured to drive one or morejoints kinematically joining the plurality of links to move the linksaccording to the reconfiguration command and the calculated movement soas to maintain a desired state of the end effector.
 56. The roboticsystem of claim 55 further comprising: an input for receiving amanipulation command to move the end effector with a desired endeffector movement, the input being disposed on a user interface, whereinthe processor is further configured to calculate an end effectordisplacing movement of the links in response to the manipulationcommand, wherein calculating end effector displacing movement of thelinks comprises calculating joint velocities within anull-perpendicular-space of the Jacobian, the null-perpendicular-spacebeing orthogonal to the null-space, and wherein the processor is furtherconfigured to drive the joints kinematically coupling the linksaccording to the calculated end effector displacing movement of thelinks to effect the desired end effector movement.
 57. The roboticsystem of claim 55, wherein a first link of the manipulator arm isjoined to the proximal base by a joint such that the first link ismoveable relative to the proximal base while the links are movedaccording to the reconfiguration movement.
 58. The robotic system ofclaim 57, wherein the joint coupling the first link to the base is arevolute joint that supports the joints of the manipulator arm such thatjoint movement of the revolute joint pivots one or more links of themanipulator arm about a pivotal axis of the revolute joint, the pivotalaxis extending from the revolute joint toward the end effector.
 59. Asurgical robotic system comprising: a surgical instrument having aproximal end, a distal end effector suitable for insertion into apatient, and an intermediate portion having an insertion axistherebetween; a manipulator arm configured to support the proximal endof the instrument so as to pivot the instrument from outside thepatient, wherein the manipulator arm and instrument include a pluralityof driven joints, the joints providing sufficient degrees of freedom toallow a range of joint states for a given state of the end effector,wherein the joints of the manipulator comprise remote center jointsconfigured to mechanically constrain movement of the distal portion topivot about a remote center pivot point along the insertion axis andadjacent a minimally invasive aperture; an input drive for receiving areconfiguration command to move a first set of joints of the pluralitywith a desired reconfiguration movement; a processor coupling the inputto the manipulator arm and instrument, the processor configured tocalculate movement of the joints in response to the reconfigurationcommand so that the calculated velocities of the joints are within anull-space of the Jacobian, wherein the processor is further configuredto drive the joints according to the reconfiguration command and thecalculated movement so as to maintain the intermediate portion at thepivot point.
 60. The robotic system of claim 59 further comprising: aninput for receiving a manipulation command to move the end effector witha desired end effector movement, the input being disposed on a userinterface and separate from the input device for receiving thereconfiguration command, wherein the processor is further configured tocalculate an end effector displacing movement of the joints in responseto the manipulation command, wherein calculating end effector displacingmovement of the joints comprises calculating joint velocities within anull-perpendicular-space of the Jacobian, the null-perpendicular-spacebeing orthogonal to the null-space, and wherein the processor is furtherconfigured to drive the joints according to the calculated end effectordisplacing movement of the joints to effect the desired end effectormovement and maintain the intermediate portion at the pivot point. 61.The robotic system of claim 60, wherein the processor is configured tocalculate joint movement so that the first set of joints is not drivenwhen calculating the end effector displacing movement of the joints. 62.The robotic system of claim 59, wherein the processor is configured tocalculate joint movement so that a first joint from the first set ofjoints provides a substantially constant speed of the first joint for aduration of the reconfiguration command.
 63. The robotic system of claim59, wherein the input device for receiving the reconfiguration commandis disposed on a portion of the manipulator arm such that entering acommand using the input device drives an adjacent joint so as to movethe portion of the manipulator arm on which the input device is located.64. The robotic system of claim 59, wherein the input device forreceiving the reconfiguration manipulation command comprises a buttoncluster, wherein the button cluster comprises a plurality of buttons,each button corresponding to a different joint of the plurality.
 65. Therobotic system of claim 59, wherein the input device for receiving thereconfiguration manipulation command comprises a joystick such that theplurality of joints are selectively driveable by movement of thejoystick.
 66. The robotic system of claim 59, wherein a proximal portionof the manipulator arm is coupled to the base by a first joint.
 67. Therobotic system of claim 66, wherein the first joint is a revolute jointthat supports the joints of the manipulator arm such that joint movementof the revolute joint pivots one or more joints of the manipulator armabout a pivotal axis of the revolute joint, the pivotal axis extendingfrom the revolute joint through the remote center.
 68. A surgicalrobotic system comprising: a surgical instrument having a proximal end,a distal end effector suitable for insertion into a patient, and anintermediate portion extending along an insertion axis therebetween; amanipulator arm configured to support the proximal end of the instrumentso as to move the instrument from outside the patient so that theintermediate portion pivots about a remote center, wherein themanipulator arm includes a plurality of kinematically joined links, someof the links comprising remote center links coupled together by remotecenter joints configured to mechanically constrain movement of theinsertion axis to rotation about first and second remote center axestraversing the insertion axis extending through the remote center; aninput for receiving a reconfiguration command to move at least one linkof the plurality with a desired reconfiguration movement, the inputcoupled with the manipulator so that a first set of joints of themanipulator is driven per the desired movement in response to thecommand and driving of the first set of joints pivotally moves theinsertion axis about a first set of joints' axes, the first set ofjoints' axes traversing the insertion axis through the remote center,the first set of joints' axes being angularly offset from the first andsecond remote center axes.
 69. The robotic system of claim 68 furthercomprising: a processor coupling the input to the manipulator arm,wherein the processor is configured to calculate a reconfigurationmovement of the links within a null-space of a Jacobian of themanipulator arm in response to reconfiguration command.
 70. The roboticsystem of claim 69 further comprising: an input for receiving amanipulation command to move the end effector with a desired endeffector movement, the input being disposed on the user interface andseparate from the input for receiving the reconfiguration command,wherein the processor is further configured to calculate an end effectordisplacing movement of the links in response to the manipulationcommand, wherein calculating end effector displacing movement of thelinks comprises calculating velocities of the joints within anull-perpendicular-space of the Jacobian, the null-perpendicular-spacebeing orthogonal to the null-space, and wherein the controller isfurther configured to move the links according to the calculated endeffector displacing movement by driving one or more joints kinematicallycoupling the links to effect the desired end effector movement.
 71. Therobotic system of claim 69, wherein the user interface comprises asurgeon console and a patient side cart, the manipulation input beingdisposed on the surgeon console and the reconfiguration input beingdisposed on the patient side cart.
 72. The robotic system of claim 69,wherein the user interface comprises a surgeon console and a patientside cart, the manipulation input being disposed on the surgeon consoleand the reconfiguration input being disposed on the surgeon console. 73.The robotic system of claim 69, wherein the user interface comprises asurgeon console and a patient side cart, the manipulation input beingdisposed on the patient side cart and the reconfiguration input beingdisposed on the patient side cart.
 74. The robotic system of claim 68,wherein a proximal portion of the manipulator arm is coupled to the baseby a joint such that the proximal portion of the manipulator arm ismoveable relative to the base when the links are moved according to thereconfiguration movement.
 75. The robotic system of claim 74, whereinthe joint coupling the proximal portion to the base is a revolute jointthat supports the links of the manipulator arm such that joint movementof the revolute joint pivots one or more links of the manipulator armabout a pivotal axis of the revolute joint, the pivotal axis extendingfrom the revolute joint toward the remote center.